HUMAN
SYSTEMS:
Circulatory System
BLOOD
BLOOD
 Fluid
connective tissue
 Circulates
 About
 Blood
various substances
5L of blood in human adults
is a part of the cardiovascular system
(other include the heart and blood vessels)
COMPONENTS OF BLOOD

Blood contains
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Plasma
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plasma (fluid component)
Blood cells (suspended component)
Contains dissolved substances (water, minerals, proteins,
carbohydrates, other complexes, etc.)
Blood cells
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RBC - Red blood cells (hemoglobin – transport of gases)
WBC - White blood cells (immune system – defense against
infections)
Platelets (involved in blood clotting)
BLOOD CELLS

Red blood cells
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Transport oxygen
Contain hemoglobin
Most abundant cell type
BLOOD CELLS

Platelets
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Small in size, pieces of larger cells found in bone marrow
Remain in circulation for 5-10 days
Role in blood clotting
BLOOD CELLS

White blood cells
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Destroy pathogens
Help in wound cleaning
Modes of action
Some search tissues for pathogens
 Some WBCs produce antibodies
 Some WBCs produce other chemicals
against pathogens
 Other eliminate dead or damaged body cells

FUNCTIONS OF BLOOD

Transport of oxygen

Transport of nutrients and minerals

Transport hormones and other substances

Regulation of body temperature
BLOOD PRESSURE
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When heart contracts, blood is pushed out
The force blood exerts on the walls of arteries is known as
blood pressure
Expressed in terms of millimeters of mercury (mm Hg)
Blood pressure is expressed by two numbers - systolic and
diastolic
Systolic pressure – pressure in arteries when heart
contracts
Diastolic pressure - pressure in arteries when heart relaxes
Healthy blood pressure: systolic 120 mm Hg, diastolic 80 mm
Hg
Pulse – rhythmic throbbing of arteries when blood is pumped
by heart (around 60 - 70 per minute)
BLOOD TYPES

ABO system
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A, B, AB or O
Depends on the type of antigens on RBC
Blood groups and transfusion
BLOOD TYPES

Rh System

Another type of antigen on RBC
If antigen if present then Rh+
If absent then the individual is Rh-

Rh system and transfusion
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BLOOD DISORDERS

Hemophilia
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Leukemia
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Problem in blood clotting
Protein required for clotting is missing
Blood cancer
Healthy blood cells are not produced
Sickle cell anemia
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Mutation in hemoglobin
Results is deformed RBCs
CARDIOVASCULAR
SYSTEM
CARDIOVASCULAR SYSTEM
Circulatory fluid (blood)
 Channels / tubes (blood vessels)
 Pumping device (heart)

Transport of substances
 Regulation of body temperature
 Maintenance of homeostasis

THE HEART
Muscular organ
 Divided into four compartments (chambers)
 Upper chambers: Atrium
 Lower chambers: Ventricles
 Left and right sides of the heart are separated by wall

Valves prevent back flow of blood
 Repeated opening and closing of valves produce heart
beat

BLOOD VESSELS
Hollow tubes for flow of blood
 Some contain valve to prevent backward blood flow
 Three types

 Arteries
Carries blood away from the heart
 Pulse is caused by flow of blood into arteries
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 Capillaries
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Narrow blood vessels
Allows exchange between body cells and blood
 Veins
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Blood enters from arteries to veins
Carry blood towards heart
BLOOD VESSELS
TYPES OF CIRCULATION
1.
2.
Pulmonary circulation
Systemic circulation
CARDIOVASCULAR PROBLEMS

Atherosclerosis
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Cholesterol and lipids accumulate in blood vessels
This causes narrowing of vessels and decrease in
elasticity
High blood pressure
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Hypertension
Narrowing or constriction of blood vessels increases
pressure
Stroke - blockage or rupture of blood vessels in brain
CARDIOVASCULAR PROBLEMS
CARDIOVASCULAR PROBLEMS

Heart attack and failure
 Heart attack - when heart muscle cells do not get
enough food
 Damage to heart cells
 If damage is excessive, heart may stop
Heart failure occurs when heart is too weak to
pump sufficient blood to meet body’s need
 Organs such as lungs, brain or kidneys may get
damage
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